Paul BiggarMost powerful language features to enable reliable software and fast iteration:
- immutability
- enums (sum types/variants)
- static types (real ones, not like java/C++)
- higher-order functions (eg map/filter)
Nothing else comes close
Joachim 
@paulbiggar what exactly is missing in static types of Java/c++?
Paul Biggar (@[email protected])
@[email protected] Null, and the role that dynamic casting and (for java) the Object type have in the ecosystem (one could say the same about void*, but it feels less pervasive)